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# Physics equation help! potential difference = current x resistance? watch

1. I'm finding that a few of my resources display this equation differently. My revision books and some BBC bitesize pages say potential difference = (current)^2 x resistance, but others say that you don't need to square the current? Anyone know which one is correct? Does it matter? Why are there two different equations?

Any help really appreciated
Thanks, Rachael
2. not sure why there are 2 but V=IR is the right one where v is pd, i is current and r is resitance.
3. (Original post by rdexcite)
I'm finding that a few of my resources display this equation differently. My revision books and some BBC bitesize pages say potential difference = (current)^2 x resistance, but others say that you don't need to square the current? Anyone know which one is correct? Does it matter? Why are there two different equations?

Any help really appreciated
Thanks, Rachael
it should be Power = I2 R
http://www.bbc.co.uk/bitesize/standa...ce/revision/2/

which page are you looking at?
4. (Original post by rdexcite)
I'm finding that a few of my resources display this equation differently. My revision books and some BBC bitesize pages say potential difference = (current)^2 x resistance, but others say that you don't need to square the current? Anyone know which one is correct? Does it matter? Why are there two different equations?

Any help really appreciated
Thanks, Rachael
It's just V=IR for V (potential diff.), I (current) and R (resistance)

Maybe the source got mixed up with a form of the Power equation P=(I^2)R . This comes from P=IV then subbing in IR for V
5. oh i got it!! the I squared times R is for power.
P=IV (1)
V=IR (2)
sub (2) into (1)
P= I * IR
P=I2R
6. OMG I totally just mixed up the equations for power and potential difference in my head. Thanks for helping me realise I'm a doofus... maybe time for a break

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